Product Description:

The 131B6688 is a VLT HVAC Drive manufactured by Danfoss within the VLT FC 102 HVAC Drives series. As a variable-frequency drive, it modulates the speed of centrifugal fans, pumps, and compressors to match real-time building demands, lowering energy use while maintaining climate control. The unit sits between the line supply and an induction motor, converting fixed-frequency power into regulated output power that allows automation systems to govern airflow or water flow through PID loops and network commands. This arrangement lets the motor respond to changing demand instead of operating continuously at full speed, which can reduce unnecessary mechanical loading during periods of lower demand.

Electrical integration centers on a supply range of 380–480 VAC, accommodating common low-voltage power systems used in commercial and industrial facilities. Operation with three-phase power balances the current draw across the incoming phases and supports the connected motor load. The enclosure has an ingress protection rating of IP55 / Type 12, helping protect the internal electronics against dust and hose-directed water encountered in mechanical rooms. An embedded EMC network classified as RFI Class A1/B (C1) attenuates conducted electrical noise and can reduce the need for a separate external filter. The design incorporates an integrated mains disconnect on the line side, allowing the incoming supply to be isolated directly at the drive. This disconnect supports controlled shutdown and access without requiring a separate disconnect enclosure next to the unit.

Connection hardware uses standard cable entries, allowing motor, line, and I/O wiring to pass through common metric cable glands without additional entry plates. For HVAC loads that rarely regenerate energy, the unit operates with no brake chopper, avoiding circuitry intended to route regenerated power through a braking resistor. Daily parameter changes are handled at the drive face through the graphical local control panel, which presents settings, operating values, alarms, and status information without requiring a separate interface. The control boards use uncoated printed circuit board construction, which is suitable for indoor locations with filtered air and controlled exposure to airborne contaminants. Network communication can be added when the building automation design requires remote commands, operating data, or integration with supervisory controls.